GATE EE Mock Test 1 (20 Questions, Free)
A free GATE Electrical Engineering mock test with 20 original questions on circuits, fields, signals, machines, power systems, control and power electronics.
This mock test has 20 original GATE-style questions across the electrical engineering syllabus. Give yourself 60 minutes, write your answers on paper, then open each question to check. Score +1 per correct answer and −1/3 per wrong MCQ.
Circuits and fields
Three resistors of 6 Ω, 3 Ω and 2 Ω are connected in parallel. What is the equivalent resistance in Ω?
Show answer and explanation
Answer: 11/R = 1/6 + 2/6 + 3/6 = 1, so R = 1 Ω.
A source with Thevenin voltage 20 V and resistance 4 Ω feeds a load chosen for maximum power transfer. What is the maximum power in W?
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Answer: 25P_max = V_th²/(4R_th) = 400/16 = 25 W.
An RC circuit has R = 10 kΩ and C = 100 µF. What is its time constant in seconds?
Show answer and explanation
Answer: 1τ = RC = 10⁴ × 10⁻⁴ = 1 s.
A load draws 10 A at 230 V with power factor 0.8 lagging. What is the real power in W?
Show answer and explanation
Answer: 1840P = VI cos φ = 230 × 10 × 0.8 = 1840 W.
A parallel-plate capacitor in air has its plate gap doubled and a dielectric with ε_r = 4 inserted to fill it. The capacitance becomes:
Show answer and explanation
Answer: CC = ε₀ε_r A/d: ε_r × 4 and d × 2 give a net factor of 2.
Signals and control
A causal LTI system has transfer function H(s) = 1/((s + 1)(s − 2)). It is:
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Answer: BThe pole at s = +2 is in the right half-plane, so the causal system is unstable.
A unity-feedback system has open-loop G(s) = 10/(s(s + 2)). What is the steady-state error for a unit ramp input?
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Answer: 0.2K_v = lim s·G(s) = 10/2 = 5, so e_ss = 1/K_v = 0.2.
For the closed loop of G(s) = 16/(s(s + 4)) with unity feedback, what is the damping ratio?
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Answer: 0.5Closed loop: 16/(s² + 4s + 16), so ω_n = 4 and 2ζω_n = 4, giving ζ = 0.5.
What is the peak overshoot (as a fraction) of a second-order system with ζ = 0.5? (Give 3 decimal places.)
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Answer: 0.163M_p = e^(−πζ/√(1 − ζ²)) = e^(−1.814) ≈ 0.163.
Machines
A 2200/220 V transformer has a secondary current of 50 A. What is the primary current in A (ideal transformer)?
Show answer and explanation
Answer: 5I₁ = I₂ × V₂/V₁ = 50 × 220/2200 = 5 A.
What is the synchronous speed in rpm of a 6-pole, 50 Hz machine?
Show answer and explanation
Answer: 1000N_s = 120f/P = 6000/6 = 1000 rpm.
An induction motor has air-gap power 10 kW and slip 0.05. What is the rotor copper loss in W?
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Answer: 500Rotor copper loss = s × P_ag = 0.05 × 10000 = 500 W.
A transformer has full-load copper loss 400 W and core loss 100 W. At what fraction of full load is efficiency maximum?
Show answer and explanation
Answer: 0.5Maximum efficiency when x² × 400 = 100, so x = √0.25 = 0.5.
Power systems
A lossless line has V₁ = V₂ = 1 pu and X = 0.5 pu. What is the maximum power it can transfer in pu?
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Answer: 2P_max = V₁V₂/X = 1/0.5 = 2 pu.
The Thevenin impedance at a bus is 0.2 pu. What is the three-phase fault current in pu (prefault voltage 1 pu)?
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Answer: 5I_f = 1/Z_th = 5 pu.
An impedance of 0.1 pu on a 50 MVA base is converted to a 100 MVA base at the same voltage. What is the new per-unit value?
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Answer: 0.2Z_new = Z_old × S_new/S_old = 0.1 × 2 = 0.2 pu.
Electronics, power electronics and measurements
A boost converter has input 12 V and duty ratio 0.6. What is the output voltage in V?
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Answer: 30V_o = V_in/(1 − D) = 12/0.4 = 30 V.
An ideal inverting op-amp amplifier has R_f = 100 kΩ and R_in = 10 kΩ. What is its voltage gain?
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Answer: -10Gain = −R_f/R_in = −10.
A meter with resistance 9 Ω and full-scale current 10 mA is to read 100 mA. What shunt resistance in Ω is needed?
Show answer and explanation
Answer: 1R_sh = I_m R_m/(I − I_m) = 0.01 × 9/0.09 = 1 Ω.
Which of these are fully controlled power switches (can be turned on and off by the gate)? (Select all that apply.)
Show answer and explanation
Answer: A, BIGBTs and MOSFETs turn on and off by gate control. A diode is uncontrolled and an SCR cannot be turned off by its gate.
Your score
| Score (out of 20) | What it means |
|---|---|
| 16 and above | Strong: move to full-length papers |
| 10 – 15 | Revise the subjects where you lost marks |
| Below 10 | Go back to the lessons, then retake after two weeks |
Revise with the formula sheet and follow the study plan.